Mobile devices are increasingly being used to interact with other connected devices to solve real world problems. For example, there are many new applications and services that simplify home automation tasks, such as network-enabled enabled door locks and lamps. These applications and services may rely on technologies like BLUETOOTH™, near field communication (NFC), audio, or other technologies in order to determine presence in order to provide value and hopefully a secure experience. As a result of these technologies and others, a mobile device's proximity and interactions with other devices should be secure. As an example, if someone steals a mobile device and a home or workplace door can be unlocked with the mobile device, the thief can now access the home or workplace. Other types of security problems involving mobile devices may include access to financial services or access to confidential information.